The present invention relates to editing of a video signal, such as a system for reproducing video from several sources, editing the reproduced video and recording the edited video signal.
Broadcasting stations have conventionally edited video from several sources, referred to as source tapes, and recorded the result, referred to as a broadcast or commercial (CM) tape, on a video tape cassette.
FIG. 1 shows an example of a conventional edit system. Video tape cassette 1 serving as the source tape is loaded into and reproduced by reproducing VTR 2. The reproduced signal is processed by digital multi-effector (DME) 7. Broadcasting video tape cassette 13 is loaded into recording VTR 8 which serves to record an output from DME 7 on the broadcasting video tape cassette 13. If special effects capabilities are not required, instead of the DME 7, an editor may be used and the reproducing VTR 2 and the recording VTR 8 may be combined.
In the reproducing-side VTR 2, a reproducing head 3 is connected to one fixed contact 5a of a head change-over switch 5, and a reproducing head 4 is connected to the other fixed contact 5b of the head change-over switch 5. The switch 5 selectively connects its movable contact 5c to one or the other fixed contact 5a or 5b based on a switching signal supplied to a VTR main body 6 from a system controller, not shown.
If the reproducing VTR 2 is either an analog VTR or digital VTR, then video and audio signals output from the reproducing VTR 2 are supplied to the DME 7 at transfer rate of 60 fields/second when the video and audio signals are NTSC signals, and are supplied thereto at transfer rate of 50 fields/seconds when the video and audio signals are PAL signals.
The DME 7 includes analog video and audio input terminals and digital video and audio input terminals. The DME 7 is adapted to perform special effect processing on the video signal from the reproducing VTR 2, such as mosaic effect, movement, reduction, magnification, rotation of image or the like, based on the transfer rate of 60 fields/seconds if the video signal is the NTSC video signal and based on the transfer rate of 50 fields/second if the video signal is the PAL video signal. An output of the DME 7 is supplied to the recording VTR 8.
The recording VTR 8 includes a recording head 9 connected to one fixed contact 11a of a head change-over switch 11 and a recording head 10 connected to the other fixed contact 11a of the head change-over switch 11. The switch 11 selectively connects its movable contact 11c to one or the other fixed contact 11a or 11b based on a switching signal supplied to the VTR main body 12 from the system controller, not shown. The recording VTR 8 is operative to record the signal output from the DME 7 on the video tape cassette 13 on the basis of the transfer rate of 60 fields/second if the video signal is the NTSC video signal and the transfer rate of 50 fields/second if the video signal is the PAL video signal.
[0011]
The same assignee of this application has previously proposed, in Japanese patent application No. 5-87413, an edit apparatus comprising display means on which first and second points of predetermined-unit image data are displayed, designating means for designating the predetermined-unit image data of the first and second points displayed on the display means and control means for displaying time code data of the first or second point image data designated by the designating means, status and identification number of associated equipment to thereby improve edit efficiency and utilization factor, e.g., edit apparatus capable of carrying out edit work without carrying out a cumbersome work, such as checking a plurality of VTRs through the reproduction and confirming and inputting memory address or the like through a keyboard or the like by changing contents of edit files EDL1 to EDLn by deleting, copying, moving and replacing edit-unit image data displayed on a picture screen, for example, by means of a pointing device or keyboard. Thus, edit work can be carried out efficiently.
The video editing system shown in FIG. 1 has several drawbacks.
Since the transfer rate for the source and broadcast video signals in FIG. 1 is determined based on the field of frame frequency of the video signal, the processes of reproducing the source video and recording the broadcast video consume more time than is necessary. Specifically, the conventional NTSC and PAL frame frequencies are determined based on human perception, whereas reproduction and recording in a video editing system need not be constrained by human perceptual rates.
If the source video is drawn from many tapes, it takes a long time to assemble these sources for use by the DME 7.
The work efficiency of the operator is particularly deteriorated when it is necessary to dub or revise, that is, again carry out processing with the DME 7, because the source video must be rewound to the original tape position and the entirety of the process of signal reproduction must be repeated.
If the source video is repeatedly reproduced, there is also the increased possibility that a precious source tape will be damaged.
When multiple recordings are made on the broadcast video tape cassette, the video cassette contains a number of edit points composed of magnetic tracks formed by the previous-recording process and magnetic tracks formed by the present recording processing. When the broadcast video tape cassette 13 having many such edit points is reproduced, there is the possibility that a picture will be disturbed at such edit point or that a reproduced picture will be influenced by the edit point.
Furthermore, if editing involves mixing and switching from multiple sources, it is necessary to increase the number of the reproducing VTRs as the number of sources increases.